Biochemical and cellular aspects of the carbohydrate metabolism and hydrolase systems of the parasitic flagellate Trichomonas vaginalis are continued to be studied. In addition major emphasis will be put on the elucidation of the action of the antitrichomonad drug, metronidazole. The following major questions will be explored in this year. Utilizing chromatographic methods we will establish the carbon balance and H2 production of T. vaginalis under anaerobiosis and aerobiosis. The same parameters will be studied on cells exposed to nitroimidazoles to elucidate the action of these drugs on metabolism. The enzymes involved in the hydrogenosomal acetate production (acetate:succinate CoA transferase, succinate thiokinase and acetate thiokinase) will be partially purified and their properties studied. The study of the hydrolases will continue with special emphasis on the purification and characterization of neutral proteases which may play a role in the pathogenesis of trichomoniasis. BIBLIOGRAPHIC REFERENCES: Muller, M. and Lindmark, D.G., (1976). Uptake of metronidazole and its effect on viability in trichomonads and Entamoeba invadens under anaerobic and aerobic conditions. Antimicrob. Ag. Chemother. 9, 696-700. Larusso, N.F., Lindmark, D.G., and Muller, M., (1976). Hepatic metabolism and biliary excretion of metronidazole. Gastroenterology 70, 905 (abstract).